The current implementation of isPortAvaialble actually tries to bind to it in the CommandBox process. This presents an issue for users who want to run CommandBox as an ordinary user but want to start a server that binds to port 80. See ticket
Look at the feasibility of using a native tool such as netstat to test for what ports are available. Note, we'd need to get the IP address bound to the hostname first and then check to see if that port is bound to that specific IP or all IPs. The same port bound to another IP should return false.